1. Field of the Invention
The present invention relates to an air nozzle suitable for producing a sheath-core type fancy yarn in which a sheath yarn is entangled around a core yarn to form a plurality of loops by a suction vortex caused in the air nozzle.
2. Description of the Prior Art
A prior art air nozzle, disclosed in Japanese Unexamined Patent Publication (Kokai) No. 53-14856 by the persent inventors, comprises a hollow cylindrical body having a first inlet for a core yarn at one end thereof and at least a second inlet for a sheath yarn and a third inlet for operating fluid. The second and third inlets are tangentially bored in a circumferential wall of the body in the vicinity of the other end thereof. The body is further provided with a suction orifice for the fluid in its circumferential wall in the vicinity of the first inlet. The air nozzle further comprises a conical cap having a yarn draw-off passage through an axis thereof, coaxially inserted into the body through the other end of the body. The apex of the cap is disposed between the suction orifice and the second inlet to form an annular space between the inner surface of the body and the outer surface of the conical cap.
The prior art air nozzle, however, was found to be unsuitable for a tightly entangled fancy yarn having a plurality of uniform loops, even with strictly controlled process conditions.
Another problem with the prior art was that the resultant fancy yarn was easily separated into the starting yarns during post-processing such as knitting or weaving.